A camshaft actuates intake and exhaust valves of an internal combustion engine. In a dual overhead camshaft configuration, the engine includes an exhaust camshaft and an intake camshaft for each bank of cylinders. Rotation of the camshafts actuates the intake and exhaust valves. Position and timing between a crankshaft and the camshaft is critical for proper synchronization of spark and fuel.
An engine control system may include one or more camshaft phasing devices (cam phasers). For example, the cam phaser may create a continuously variable rotational offset between the exhaust camshaft and the intake camshaft and/or the crankshaft. Typically, cam phasers receive position and timing information from camshaft position sensors. The camshaft position sensor typically includes a variable reluctance or Hall Effect sensor that senses the passage of a tooth, tab, and/or slot on a target data wheel coupled to the camshaft.
The position sensor sends a signal to a control module. The control module develops an offset signal to control the cam phasers coupled to the camshafts. For example, the control module may be an engine control module. Alternatively, the control module may be a stand-alone controller or combined with other onboard controllers. The control module includes a processor and memory such as random access memory (RAM), read only memory (ROM) or other suitable electronic storage. Conventionally, internal combustion engines include one cam position sensor for each cam phaser. For example, in a dual-overhead cam arrangement, two cam position sensors are required to control the two cam phasers.